Mikhail Lesin who was recently found dead at Du Pont Circle in Washington D.C. serves as an almost perfect poster face of Russian oligarchy--he was a minister of the press under Yeltsin and under Putin, then he headed Gazprom-Media, which also controls the "fifth column" oppositionist Echo Moskvy. He was a member of the highest government and oligarchic structures ruling Russia. Around 2013 he bought himself four luxurious properties in Beverley Hills for $28 million. He has been under the FBI investigation for corruption and money laundering.
Russian oligarchs want to live and enjoy their money in the West (rather than in Russia), and not only in the West, but, if possible, in the most glamorous places--much like the nouveaux riches tried to get into the old aristocracy.
However, this also means that the US and its various agencies are now in a perfect position to decide whether they want to let these oligarchs in and legitimize them and their money or/and also decide at ease under what conditions and terms this can be allowed or blocked. The rest is just a matter of negotiations which has always been a US strength developed to an art.
The bottom line is the Russian oligarchs suffer from an ardent desire to be accepted and legitimized by the West, and the West is the gatekeeper and also the policeman guarding the passage to the Holy of the Holies. So guess who is free to dictate the terms of the trade.